


At the Edge of a Blade

by relucant



Category: Supernatural
Genre: Angelic Grace, Angst, Angst with a Happy Ending, Episode: s10e14 The Executioner's Song, Falling Castiel, First Blade, M/M, Mark of Cain, Post s10e14, Temporary Character Death
Language: English
Status: Completed
Published: 2015-02-20
Updated: 2015-02-20
Packaged: 2018-03-13 23:27:02
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,776
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3400208
Author URL: https://archiveofourown.org/users/relucant/pseuds/relucant
Summary: <blockquote class="userstuff">
              <p>"Dean," he says.  "Look at me."</p>
<p>Reluctantly Dean drags his eyes to Castiel's face.  There are tears pooling in the shimmering blue, but a small smile curls on his lips.</p>
<p>"I've made peace with how my story ends.  I'm old, Dean.  I'm very old.  I've watched unimaginable beauty and unspeakable tragedy for millennia, without understanding what it meant.  And you changed that."</p>
<p>"Cas, don't," Dean chokes, turning his head away, and Cas is silent for a moment.</p>
<p>"My grace is fading, Dean," he finally says.  "I don't have long left."</p>
            </blockquote>





	At the Edge of a Blade

**Author's Note:**

> because Supernatural doesn't let us have nice things.
> 
> (but when I say I don't ever do unhappy endings, I promise I'm not lying.)

"No," Dean spits again. Unconsciously he grips his right forearm, scraping his thumbnail over the flesh. "Fuck, no. We been over this, Cas. Gonna find another way."

"You told me to do whatever it took," Cas reminds him gently, and he nearly screams.

They're sitting on the hood of the Impala, ignoring the warm Kansas drizzle soaking into their clothes. Not quite ignoring the drops of water sliding down jawlines, underneath collars.

"Whatever it took to take _me_ out," Dean snarls. "Dunno if you still got smitin' power left in you but you still got that knife. Not gonna let you die for me again."

"That sacrifice does not belong only to you," Cas says softly. "And my blade, I fear, would not kill you, only turn you into what you were before. Only the First Blade would penetrate the Mark, and I cannot wield that."

"Then I'll fuckin' do it myself, since I just killed the only other dude who could." He reaches for the blade at his waist, but Cas stops him with a hand at his wrist.

"Dean," he says. "Look at me."

Reluctantly Dean drags his eyes to Castiel's face. There are tears pooling in the shimmering blue, but a small smile curls on his lips.

"I've made peace with how my story ends. I'm old, Dean. I'm very old. I've watched unimaginable beauty and unspeakable tragedy for millennia, without understanding what it meant. And you changed that."

"Cas, don't," Dean chokes, turning his head away, and Cas is silent for a moment.

"My grace is fading, Dean," he finally says. "I don't have long left."

"But Metatron said --"

"Metatron is a liar by trade," Cas interrupts. "A manipulator. I will not go chasing the promises of Metatron for a fragment of my grace, to remain a shell of an angel. If the last of my grace will take the Mark from you then I give it freely, and die content."

"Fuck that," Dean snaps. "There's still plenty of dick angels runnin' around, I got no qualms gankin' some've those sons've bitches. Not you."

Cas smiles sadly. "Their grace would only feed the Mark, if forcibly taken. Who do you think would give it to you, among these 'dick angels'?" His fingers quirk into air quotes, and Dean's heart shatters further at the familiar gesture.

"I don't _care_ , Cas!" Dean cries. "Fuck, man, we don't even know if you'll die. We'll find somethin'. And we don't even know if it'll take the Mark, an' then I'll have to live with -- with _you_ dead, on top of everything else. Everyone else."

He drops his head into his hand and Cas sits quietly beside him, breathing deep and calm.

"So if that's it, then, if I kill you, like Cain killed Colette, does that mean he was right? That I -- that I'm gonna have to kill Sammy in the end?"

To his surprise, Cas laughs, small but genuine. "I thought we'd established that there's no such thing as destiny. Or have I been missing the point, all this time?" Dean snorts, not looking up, and Cas hesitates. "There is no deceit here, Dean. No one is possessing me. This is a gift, between family."

"Yeah, well, I don't fuckin' _want_ it," Dean snarls.

"I didn't say it was a gift from me to you," Cas points out quietly. "Angels are selfish creatures as well, Dean. I would prefer not to die slowly, helplessly, watching the Mark consume you while my grace crumbles. Until I am killed at the whim of a common monster, if I am lucky, before it fades completely, and I die alone and screaming."

"God, Cas," Dean chokes, turning his head into the angel's shoulder, not bothering to wipe away the tears mixing with the rain. "Never thought it would end like this. Not like this."

Cas touches the side of his neck. "It's not ending, not really. I'll see you again, someday. I still have faith, after all of this time."

"Makes one of us." He scrubs futilely at his face, then looks at at Cas through red-rimmed eyes. "So, what then? We just gonna do this now? Typical Tuesday evening an' shit?" He laughs without humor.

"I think it's best. My grace is fading faster by the day. I don't know how much longer I have to help you. I don't know how much longer I have at all." He stands up, holds out his hand. Dean takes it numbly, then wraps his arms around Cas' neck.

"I can't do it, Cas," he whispers. "Benny, man, I thought that was the worst thing imaginable. Not you. Not you too."

Cas squeezes him once, hard, then steps back. He runs the pad of his thumb over Dean's lips, and Dean closes his eyes.

He plucks the First Blade from Dean's belt, then pulls his right hand up, closes Dean's fingers around the handle, then wraps his own hands over Dean's, watching the fire snake through the Mark. He takes a deep breath, locks his eyes with bloodshot green, and stabs the blade into his own chest.

Cas' eyes go wide and his mouth falls open in a silent _oh_ ; he falls back against the bumper. Electric blue light begins leaking out along the handle, over their joined hands, a few droplets at a time and then a steady stream.

As soon as the light reaches the edge of the Mark a hissing sound fills the air, and the smell of burning flesh. Dean instinctively tries to jerk away with a yell, but Cas grips him tight with the last of his strength.

" _Don't… let… go_ ," he croaks, still staring into Dean's eyes.

"I won't," Dean promises. "I won't let go."

The stream of light slows to a trickle, and Cas' eyes begin to slip shut as the angry red lines of the Mark are replaced by blue. As the last drop slides down his wrist, he gives Dean a tiny smile, and his head falls back with a sigh.

The second Cas' eyes close for the last time the Mark ignites like fire, and at the same time the long-dead handprint on his shoulder erupts in twin agony. He stumbles back, vision blurring with the pain, and falls to his knees, left hand wrapped around the Mark and right hand clutching his bicep. It's pain like he hasn't felt since the Pit, like hot pokers searing into his skin, and he screams endlessly at the empty sky.

Eventually, after what could have been minutes or hours or another forty years, the pain begins to subside, and he collapses to the wet earth, too numbed by exhaustion to think or feel.

Something stirs above him, and his consciousness crawls slowly back to him, like a dog. The smell of soil and rain fills his nostrils, still tinged by the scent of charred flesh. He sits up slowly, not opening his eyes until he hears the sound of a wet thump, and sees Cas' body fall to the ground.

His ears ring and his vision goes staticky, and he's almost sunk back into blessed unconsciousness when he hears a small groan nearby, then a rattling cough.

Immediately he's on his feet, clutching the trunk of the Impala for support against the dizziness.

"Cas?" he whispers, dropping to his knees. There's no answer, but a shiver runs through Cas' body. One eye cracks open, then the other, and Cas reaches out a shaking hand to touch Dean's face.

"Cas… Are we in Heaven? Did I die too?"

Cas blinks at him, then sits up with a groan. "I don't believe so. This is not my Heaven, at least. Nor yours, I believe, without Sam." He rubs his eyes. "Did it work?"

Dean stares at him for a moment, gaping. The memory of the Mark, the brand, the unbelievable pain were already distant and unimportant, at the sight of Castiel sitting up against the car.

"Did it _work_? Dude, I stabbed you in the heart. I _killed_ you."

"The headache I am currently experiencing suggests otherwise," Cas said grumpily. He glances down. His shirt is still ripped open over his chest, but only a small, shiny scar is apparent on his skin.

Dean stares at him a moment before it clicks. "Are you -- are you _human_ again?"

Cas shrugs. "I believe so," he says carelessly, then reaches for Dean's arm. He brushes his hand down the unblemished skin, then looks up with a smile.

Dean automatically follows his eyes, then pulls up his left shirt sleeve, revealing the smooth skin, pale in the moonlight.

"Did you," he begins, emotions warring violently inside him. "Did you _know_ this was going to happen? And you didn't -- _tell_ me?"

"No," Cas says quietly. He reaches over and entwines their hands together, and Dean's fingers flex convulsively, unwilling to let go. "I thought I would die, as expected. I'd made my peace with it." He pauses. "But I didn't know -- not for sure --" He breaks off again, chewing his lip, then takes a deep breath. "No angel has been so close to humanity as I have been. No angel has loved a human as I love you, Dean. There is no precedent for this."

"But why -- why didn't you tell me this?"

"I didn't dare hope," Cas admitted. "I didn't want to give you hope -- for you to spend your life half-expecting to see me alive somewhere, like before."

"I dunno whether to punch you or kiss you, man," he says before he can stop himself.

"I'd prefer you refrain from the punching," Cas says with a tired smile. "I believe this may be my… 'final regeneration,' as they say."

Dean stares at him, then breaks into a choking laugh. "Jesus Christ. On the long list of reasons to kill Metadouche, fillin' your head with pop culture is up there." 

He scoots closer until they're both propped against the bumper, letting the rain wash away the streaks of dirt, and without thinking he turns and presses a kiss to the corner of Cas' mouth. Cas makes a small, surprised sound, then tilts his head so that their lips slide together easily. Dean tries to pour everything he's never been able to say into the kiss, all the jumbled-up feelings he's suddenly too tired to repress, and he thinks he gets his answer in the soft thumb that comes up to stroke his jawline.

Finally they break away, breathing unsteadily. Cas blinks at him, as though expecting an explanation, and he shrugs.

"Final regeneration, huh?" he says with a weak smile. "Might as well make it a good one."

**Author's Note:**

> find me on [tumblr](http://relucant.tumblr.com) or [twitter](https://twitter.com/relucanting). I'm nice.


End file.
